Studies Find Concerning Rates of Persistent Opioid Use After Common Foot and Ankle Procedures

Two studies examining opioid use by patients treated for foot and ankle conditions show that a substantial number of the patients continued to consume opioids persistently after the therapeutic course for pain had concluded.

The studies, presented at the American Orthopaedic Foot & Ankle Society annual meeting in Boston, found that in those who underwent surgery for hallux valgus, the rate of new, persistent opioid use was 6.2 percent, and in patients who received open surgical treatment for ankle fracture, the rate was 8.8 percent.

The studies’ findings, both conducted by a group at the University of Michigan, show that new chronic opioid use is “a major problem following orthopaedic procedures” and point to the need to identify the factors correlated with persistent use, the authors said. Among the factors associated with new, persistent opioid use were prescribing patterns, coexisting mental health diagnoses, and certain preoperative pain disorders. The authors stated that understanding the high, persistent use rates and the risk factors that may play a role will provide a foundation upon which to address this public health problem.

Dr. Finney said that patients undergoing procedures for hallux valgus were selected because they provide “a likely reflection of opioid prescribing patterns and usage in elective forefoot procedures.”

The bunion study involved 41,687 opioid-naïve patients who underwent surgical treatment of hallux valgus with one of three designated procedures. Of those, 5,125 (12.3 percent) did not fill any opioid prescription. The remaining 36,562 patients (average age, 48.6 years; 88.1 percent female) filled no opioid prescription during the 12-month to 30-day period before treatment and filled at least one opioid prescription during the perioperative period of 30 days prior to and 14 days after surgery.

Of the final study cohort, 27,921 (76.4 percent) underwent hallux valgus correction with distal first metatarsal osteotomy, 5,769 (15.8 percent) underwent hallux valgus correction with a double osteotomy of the first metatarsal, and 2,872 (7.9 percent) underwent hallux valgus correction with metatarsal-medial cuneiform arthrodesis. Among those who filled a prescription, 16,536 (45.2 percent) did so during the 30 days prior to their surgery date.

After the study controlled for patient characteristics, the highest rate of new, persistent opioid use was observed in those treated with a first metatarsal-medial cuneiform arthrodesis (7.3 percent) (Fig. 1), followed by correction with distal first metatarsal osteotomy (control group; 6.2 percent) and correction with a double osteotomy of the first metatarsal (5.9 percent).
Patients who underwent treatment
of hallux valgus with a double
osteotomy of the first metatarsal
showed no difference in the rate of new, persistent opioid use compared to the control group (95 percent confidence interval [CI], 0.84–1.07; P = 0.38). There was a significant increase in the rate of persistent opioid use between patients treated with first metatarsal-medial cuneiform joint arthrodesis compared to the control group (95 percent CI, 1.03–1.38; P = 0.02). Rates of new, persistent opioid use by procedure are shown in Fig. 2.

The greatest modifiable risk factor for this cohort of opioid-naïve patients was a total prescribed initial opioid dose of ≥ 337.5 mg oral morphine equivalent in the perioperative period, which represented the top 25th percentile of prescribed opioid dose per patient (95 percent CI, 1.10–1.44; P = 0.001). For reference, this amount is equivalent to approximately 45 tablets of oxycodone 5 mg. Additionally, patients who filled an opioid prescription during the 30 days prior to their surgery date were more likely to continue to use opioids after the 90-day treatment period (95 percent CI, 1.02–1.22, P = 0.014). Patients who resided in geographic regions outside of the northeastern United States demonstrated significantly higher rates of new, persistent opioid use (P < 0.001). Other patient-specific factors included medical comorbidities; preexisting diagnoses of mental health disorders, including depression, anxiety, and drug and substance use disorders; and patients with back and other pain disorders. There were no differences in persistent use among age groups or household income levels.

Reporting on the ankle fracture study, Dr. Gossett presented that a total of 19,138 patients underwent open or closed treatment of an ankle fracture. Only 12.5 percent of patients who underwent surgical treatment did not fill any opioid prescription compared to 51.2 percent who underwent closed treatment.

The final study cohort comprised 13,099 patients who filled no opioid prescriptions during the 12 months to 15 days before treatment and who filled at least one opioid prescription during the perioperative or peritreatment period of 14 days prior to seven days after either open surgical (8,498, 64.9 percent) or closed treatment of an ankle fracture (4,601, 35.1 percent). The most common surgical treatment subtype was open treatment of a distal fibula fracture (26.9 percent), with the least common procedure being open treatment of a trimalleolar ankle fracture with fixation of posterior lip (2.9 percent).

Both treatment groups demonstrated high rates of new, persistent opioid use, and there was a significantly higher rate among patients who underwent open surgical treatment compared to those treated nonsurgically. Of patients who underwent open treatment of an ankle fracture, 751 (8.8 percent) filled an opioid prescription between 91 and 180 days after surgery compared to 312 patients (6.8 percent) in the closed treatment group (P < 0.001). Only 12 patients (1.1 percent) who underwent surgical treatment and had persistent opioid use were diagnosed with a neuropathic pain condition in the six months after treatment compared to 0.1 percent of patients who underwent closed treatment (P < 0.001). After controlling for patient characteristics, there was some variation in the adjusted rates of new, persistent opioid use between the surgical treatment subtypes. Compared to the closed treatment control group, two surgical treatment subtypes demonstrated significantly increased rates of persistent use: open treatment of bimalleolar ankle fracture (95% CI, 1.12–1.59; P = 0.002) and open treatment of trimalleolar ankle fracture with fixation of posterior lip (95% CI, 1.05–2.08; P = 0.02). In contrast, the two other surgical subgroups, open treatment of distal fibula fracture (95% CI, 0.84–1.22; P = 0.88) and open treatment of trimalleolar ankle fracture without fixation of posterior lip (95% CI, 0.91–1.40; P = 0.26), did not have a significantly different risk of persistent opioid use compared to the nonsurgical group.

Fig. 1 Anterior to posterior radiograph of foot following operative correction of hallux valgus with a first metatarsal-cuneiform arthrodesis. Hallux valgus correction with a metatarsal-cuneiform fusion resulted in a 7.3 percent adjusted rate of new, persistent opioid use.Courtesy of James R. Holmes, MD

Fig. 2 Adjusted rates of new, persistent opioid use by procedure. Two surgical subtypes demonstrated significantly higher rates of new, persistent opioid use (star) compared to the closed treatment control group (green bar). Courtesy of James R. Holmes, MD

An engagement effort

Drs. Finney and Gossett explained that two of the study coauthors—Chad M. Brummett, MD, an anesthesiologist who focuses on pain medicine, and Jennifer F. Waljee, MD, MPH, a plastic surgeon—are clinical scientists who codirect the Michigan Opioid Prescribing Engagement Network (M OPEN), “a diverse group of clinicians and scientists focused on this problem in a very multifaceted way.”

“We are fortunate to be working at an institution [University of Michigan] that is really leading the charge in terms of understanding and striving to mitigate the opioid epidemic in this country,” Dr. Finney told AAOS Now. He and his orthopaedic colleagues conducted the two foot and ankle studies as they learned about “the great work of M OPEN and understood that orthopaedists were definitely part of the problem; we enthusiastically began collaborating with them to be part of the solution.”

Several other studies have examined the issue of new, persistent opioid use in opioid-naïve patients and yielded similar findings. A study by Drs. Brummett and Waljee and colleagues found new-use rates of 5.9 percent and 6.5 percent in patients after “minor” and “major” surgeries, respectively. A study by Deyo et al., reported a new-use rate of 5 percent in a study of noncancer patients.

In summary, Dr. Finney said, “Rates of new, persistent opioid use, or continued opioid use beyond 90 days after surgery, are unacceptably high following both elective surgery and in the traumatic setting. Many of the procedures we analyzed—a distal first metatarsal osteotomy or fixation of an isolated distal fibula fracture, for example—not only are very common procedures in orthopaedics but are often considered relatively minor surgeries. Yet 6.2 percent and 7.4 percent of these patients, respectively, develop persistent opioid use. The greatest modifiable risk factor in both these studies was the initial dose of opioid prescribed, as patients who received an initial opioid dose in the top 25th percentile were significantly more likely continue to use opioids. In addition, patient-specific factors associated with new, persistent opioid use included certain mental health disorders, pain disorders, comorbid health conditions, and tobacco use.”

Dr. Gossett concluded, “These findings indicate that new, persistent opioid use is one of the most common complications of operative bunion correction, as well as operative and nonoperative treatment of ankle fractures, which to our knowledge has not been previously reported. Limiting the initial perioperative opioid dose is the largest single modifiable risk factor in minimizing new, persistent opioid use.”

On the issue of balancing concerns about addiction and the patient’s legitimate need for pain control, Dr. Gossett said, “We would never suggest that individual patient-provider relationships be overlooked. That said, limiting initial opioid prescriptions and engaging in a thoughtful discussion with patients about expectations of pain control, non-narcotic analgesics, and emphasizing nonpharmacologic pain management measures will all contribute to diminished overall opioid use.”

“Historically,” Dr. Finney noted, “we believe that larger prescriptions of opioids perioperatively have been given in an effort to minimize refill requests and also improve patient satisfaction, a metric to which all surgeons are sensitized. There is now good evidence in the literature that the initial amount of opioid prescribed has no effect on refill requests, nor patient satisfaction.”

Regarding areas for future research, Dr. Finney said, “We now need to zero in on optimal and appropriate perioperative opioid dosing, as well as explore and refine more broad-based perioperative pain management protocols.”